The correct answer is option 2: Respond to demands of middle-class pressure groups on an urgent basis.

In a democratic government, the minimum mandate refers to the basic responsibilities and obligations of the government towards its citizens. Option 2 suggests that a democratic government should prioritize the demands of middle-class pressure groups and address them promptly.

Middle-class pressure groups represent the interests and concerns of a significant portion of the population, and their demands often reflect the needs and aspirations of the larger society. By responding to these demands on an urgent basis, the government ensures that the voices and concerns of the middle class are heard and addressed in a timely manner.

While options 1, 3, and 4 may also be important aspects of governance, they do not specifically address the minimum mandate of a democratic government. Option 1 refers to responding to public criticism and threats to survival, option 3 refers to preempting social agitations, and option 4 refers to attending to threats to national sovereignty. These are important considerations in governance, but they are not exclusive to a democratic government`s minimum mandate.

Therefore, option 2 is the best choice as it focuses on the democratic government`s obligation to address the demands of the middle-class pressure groups.